Oscillating mechanical system of the resonance type



Sept. 1941- e. H. SCHIEFERSTEIN 2,255,820

OSCILLATING MECHANICAL SYSTEM OF THE RESONANCE TYPE Filed Oct. 20, 19383 Sheets-Sheet l y? 3;. H Lg,

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OSCILLATING MECHANICAL SYSTEM OF THE RESONANCE 'TYPE Filed Oct. 20, 1938 3 Sheets-Sheet 2 p 1941. e. H. SCHIEFERSTEIN 2,255,820

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Patented Sept. 16, 1941 I OSCILLATIN G MECHANICAL SYSTEM OF THERESONANCE TYPE Georg Heinrich Schiefersteln, Finowi'urt, nearEberswalde, Germany Application October 20, 1938, Serial In Germany July12, 1937 1 4 Claims. This invention relates to oscillating mechanicalsystems of the resonance type.

It is known that only relatively little energy could heretofore beaccumulated, per oscillation or semi-oscillation, in resonancemechanisms and Fig. 4 partly in section.

machines, and that, in consequence, for the purpose of increasing theenergy, either very many elastic means or very high frequencies ofoscillation had to be employed.

In the specification of my copending application Ser. 144,319 I havedescribed a spring which, while of most simple form, was able to beJudged in respect of its intrinsic character only after measurements hadbeen made.

In making such measurements, it was found that 210,000 cm. kgs. ofenergy can be accumulated in this novel type of elliptical spring withthe minor axis measuring 140 ms, the major axis 160 mms.,-and the length220 lnms.

Since springs of this type can also be constructed with far greaterdimensions and can also be employed in larger numbers per resonancemechanism, their capacity for storing energy is so enormous that, inaccordance with the idea underlying the present invention, resonancemachines and mechanisms can be constructed for outputs the limits ofstill unknown.

The present invention plates the employment of elastic means of theforegoing kind (of rubber or equivalent materials) in resonancemechanisms capable of 'storing periodic amounts of energy and, when setin furnishing pseudo-harmonic oscillations of any desired degree.

consequently contem- The invention also consists in the application ofsuch springs in prime movers and mac es performing work, and also inapparatus and tools.

The invention is illustratively exemplified in the accompanyingdrawings, in which Fig. 1a shows a spring element of the ty pe to beused according to the invention in elevation and partly in section,

Fig. 1b is an end view same arrangement.

Fig. 2 is an elevational view partly in section. of a spring arrangementparticularly adapted for resonance mechanism.

Fig. 3'is a partial elevational type of resonance mechanism according tothe invention. A

Fig. 4 is a similar elevational view of a second type of resonancemechanis Fig. 4a illustrates a modification of the cou-'- pling for themechanism of Fig. 4.

partly in section of the which are at present inner vcore aor to theview of a first Fig. 4b'is an end view of thearrangement of Fig. 5 is anelevational view of a. screening device constructed according to theinvention.

Fig. 5a is an end view of Fig. 5 partly in section.

Fig..5b is a side elevation of a detail in Fig. 5.

Fig. 6 is an elevational view of'another embodiment-of a resonancemechanism according to the invention,

Fig. 6a shows a modification of one of the spring members of thearrangement of Fig. 6 on a larger scale partly in elevation and partlyin section,

Fig. 6b illustrates in a similar way a modification ofthe main couplinglever,

Fig. 6c is an elevation of a driving coupling similar to that of Fig. 6,

Fig. 6d is a cross-section ofthe driving coupling of Fig. 6c. I

Figs. 7 and 8 are an elevational view, partly in section and a top planview, respectively, of still another embodiment of a resonance mechanismaccording to the invention, and

Figs. 9 and 10 are elevational views partly in section of modifiedspring arrangements.

Referring now toJthe drawings and first to Figures 1 and in, G denotesan elliptical or annular rubber ring, a the interior metal ellipse, bthe outer elliptical shell, h the long leverage arm of the spring, and cthe mounting bracket by meansof which the spring can be attached to vthe foundation or to the machine as required.

It is immaterial whether the bracket 0 is flrmly' secured to the innerelliptical core a, or to the outer elliptical ring D. The same appliesto the. lever h, which can be joined either to the outer elliptical ringb.

In the unstressed condition, 1. e.', in the central position, such aspring assumes the position 43, shown in Fig. 1.

If the spring be deflected towards the left, tension, compression andshearing stresses are set up inthe interior of the elastic'device ordevices, with corresponding resistances by means of which the axis-ratioof the ellipse, or lenticular member, or its dimensions, in respect ofsize and travel, can be variedwithin a wide range.

It has been found tobe particularly favourable that the course of theinternal resistances of the rubber should increase progressively withthe rotational moment. The increase in the stresses is the more rapid inproportion as the ratio between the major and minor axes is higher, thatis to say. the oscillation becomes more and more inthe levers 2harmonic, the higher said ratioother conditions ple shown in Fig. 1, beof comparatively light conbeing unchanged. struction.

This also correspondingly applies to the lenti-cular or other equivalentform of the springs described in the specification of my co-pendingapplication No. 144,319. r

The value of the resistance varies as the square of the width of therubber ring in Fig. 1.

The resistance of the rubber ring also varies with the thickness of itsmaterial, a greater thickness setting up a smaller resistance, and asmaller thickness a higher resistance, under otherwise equal conditions.

All these possible variations offer the advantageous possibility ofattaining any desired effeet by means of springs of this type.

Whilst the end of the leverage arm of the spring shown in Fig. 1 isdesigned as a link, of desired form, the spring shown in Fig. 2 isspecially adapted for resonance mechanisms, because the second pivotpoint of the lever is also in the shape of an elliptical spring.

This affords the advantage that the oscillation proceeds quite quietlyand noiseless, and the machine does not have tobe lubricated at anypoint.

Fig. 3 illustrates diagrammatically a resonance mechanism in which twomasses a1 and in are adapted to swing, against or with one another,depending on the actuation of the loose coup This arrangement is onlypartly balanced in respect of forces and inertia effects.

On the other hand, the arrangement shown in Fig. 4 can be fullybalanced, in known manner, I tion determined by a straight lineconnecting the two centres of gravity of the two masses a1 and in. Inthis case, the coupling can be so arranged, byusing elliptical springs,that the coupling lever k: is flrmly connected with an elliptical shafta. This shaft projects into the central rubber ellipses of two couplinglevers h, arranged on either side of the oscillating device, and setsthe said levers h in oscillation'inasmuch as through the connection ofthe elliptical inner axes, forces are generated (in the direction shownby the arrows) which are transmitted, through the rubber ellipses g1 anddc, to the massesai and b1.

Another type of coupling is shown .in Fig. 4a. In this case, thecoupling forces are transmitted-by the agency of elastic springs,f-'-from the driving motorl'M, through the coupling lever k, whichturns -with interposition of elliptical rubber rings-on a fixed axis a.

provided the movement proceeds in a direcwhen large forces have to betransmitted,

ance is doubled, and the idle energy increasesaccordingly, which may bedesirable in certain circumstances.

Fig. 5 shows a screening device in which the mass swings,-in knownmanner, between rubber calottes and is articulated by levers h withinterposition of very soft elliptical rubber rings.

The rubber calottes describe inharmonic oscillations and transmit thegreat forces of the swinging mass, while the guiding devices have onlyto hold the masses (11, In in their desired position.

By comparison with Fig. 6 the arrangement in Fig. 5 is more expensiveand complicated in construction and operation than thatEhown in Fig. 6,in which latter, the rubber members are so stoutly designed as to becapable of fully taking the oscillating forces of the masses or and b1,and

line connecting the centres of gravity of the a two masses coincideswith the direction of movement, arrangements of this kind are balancedin respect of forces and inertia effects except as regards a torqueengaging the inner rubber rings with a very smalijleverage ar-m. Asalready mentioned, complete balancing is attained in the case I of Figs.4, 4a and 4b.

A cross-section of the arrangement shown in Fig. 4 is shown in Fig. 4b,from which it can be seen that the mass or and the mass D1 are mountedintwo levers rocking on a shaft a which is firmly clamped by thebearings u.

The oscillating device can be employed as a through conveyor or screen,for which purpose are set obliquely so that they can transport thesuper-imposed material to be conveyed or screened, in one direction,after the manner of a shovel.

Ascan be seen from Fig. 4, the upper bearings of the levers it may bedesigned either as journal bearings or as elliptical rubber bearings.

In both cases, these bearings are solely guide bearings, intendedtoguide the mass or or in in such a manner that said shovelling actionis Figs. 6a, 6b and 60 show various coupling or driving means in whichelliptical rubber members are appropriately employed. In most cases,anelliptical rotational axis, inside the elliptical rubber ring' in thecoupling lever It, describes oscillations which the coupling levertransmits to the masses (11, b1, either unilaterally or bilaterally,depending on the forces.

In Fig. '7, a1 is an oscillating mass by means .of which the coupling k,a rotary unbalanced weight, is set in oscillation. h]. are verticallydisposed elliptical spring levers, ha are four horizontal ellipticalspring levers, 01 are the four foundation brackets by means of which thesprings hi are secured. on one side. to the foundation and c: are thefastening brackets by means of which the springs h: are attached to themass m.

It is obvious that such an elastic system of springs hi, ha is resilientboth horizontally and vertically. This means that the mass m, on beingsuitably energised, can perform circular oscillations of relativelylarge diameter, that is, oscillations during which each point of themass m swings in a closed circuit.

If the springs, or the rubber rings of the springs hz, be constructed soas to offer a smaller resistance than the springs hl, then the massswings in a closed circuit, in the form of an ellipse, the major axis ofwhich is vertical.

If the same experiment be performed with the springs hi, so that thespringsha exhibit the greater resistance, a swinging movement occurs ona closed circuit in which the major axis is horizontal.

It is also obvious that, when the springs in are attached directly to'the four foundation brackets 01, there will be a swinging movement 5along a vertical straight line, according to Fig. 9, and it is alsoevident that, when the levers h], are directly mounted on the bracketsc2, a hori- Iontal swinging movement must result (Fig.

All these movements, by contrast to those 91- 10 ready known, possessthe property of being able to swing, with any desired smaller or largeramplitude, depending on the length of the lever arms andthe energisingforces, so that, any desired amounts of energy can be transmitted, no

matter whether the oscillations take place on a closed circuit, astraight line or an open curve. The extraordinary advantage thusafforded by the new resonance mechanism by the use of ellipticalsprings, consists in that the range of output is so extended in alldirections that the designer is enabled, for-the first time, to fulfillwith ease the following conditions:

(1) He can dimension the springs in accordance with any requirements.-

(2) He can in all cases give the loose coupling such dimensions thatthey can transmit the desired powers without endangering any member, and

in such a manner, in relation to the real performance, that an optimumaction is obtained, in accordance with the efiect desired.

Hitherto. all these desireshave been frustrated by the limitationsimposed by the power accumuiating capacity of the elastic means.

The importance of the invention resides in that the springs enableforces and paths of any desired magnitude to be employed, therebyenabling the resonance mechanisms and machines 4 to be in this respectfully adjusted to th work to be performed, and also thattheprogressively increasing resistance of the springs can be accuratelygraduated in accordance with the requirements, in the case of primemovers, ma-

chines performing work, apparatus and tools, so that the problemsencountered can be solved in such a manner as to attain an optimumeffect.

I a i v (3) He can in all cases arrange the idle energy 30 1 In aresonance mechanism having a fixed element and a vibrating mass element,connecting means between said two elements-including a'lever and anelliptical spring on each end of said lever, each of said springscomprising a subclaim 1, in which said connecting means includes 1further a second lever having one end thereof rigid with the secondmetal member of one of said springs to normally extend at right anglesto said first lever, the other end of said second lever being connectedto one of said elements.

:3. A resonance mechanism, as claimed in claim 1, in which saidconnecting means includes a second lever having one end thereof rigidwith the second metal member of one of said springs to normally extendat right angles to said first lever, and a further elliptical spring ofthe type described having one of its, elliptical metal members rigidwith the other end of said second leverv and its second elliptical metalmember being connected to one of said elements.

4. In,a resonance mechanism, having a fixed,

element and two mass elements adaptedito oscillate relative towthe fixedelement and to'one another, means to connect the twooscillating elementswith each other and w lth the' fixed element, said means including.-atwo-arrdedlever,

and an elliptical spring at the end of-"each lever arm and atthe pivotpoint of the leve'rg'each of said springs comprisinga substantiallyelliptical metal core member, a substantially elliptical metal shellmemberl surroundingsaid core member at a distance from its surface, andanintermediate layer of soft rubber interposed between said core andshell members, one of the metal members of each spring being rigid withsaid lever, the other metal member being connected with one of saidelements.

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